Procambarus clarkii breeding and catching device

Abstract

This utility model discloses a crayfish farming and harvesting device, belonging to the technical field of aquaculture equipment, specifically relating to a crayfish farming and harvesting device. It solves the technical problems of low harvesting efficiency and inconvenient operation that may exist in existing crayfish farming and harvesting processes. The device includes multiple sequentially arranged harvesting units. Each harvesting unit includes a pair of pile foundations, an outer net, an inner net, an inverted U-shaped support, fixed pulleys, a lifting base plate, multiple guiding mechanisms, and a hydraulic system. The outer net is made of rigid material, with its top above the water surface and its bottom contacting the rigid bottom layer of the pond. The inner net is made of soft material, with its top below the water surface and its bottom hanging freely. The lifting base plate connects to the bottom of the inner net and closes its opening. The guiding mechanisms and hydraulic system achieve the raising and lowering of the lifting base plate through a counterweight bucket and a lifting main rope. This device is mainly used for crayfish farming and harvesting.

Description

Technical Field

[0001] This utility model relates to the field of aquaculture equipment technology. More specifically, this utility model relates to a crayfish farming and harvesting device. Background Technology

[0002] In the crayfish farming industry, the efficiency and reliability of the harvesting process directly affect farming profits and production management costs. Currently, traditional crayfish farming harvesting methods mainly rely on manual operation or simple harvesting devices, which have revealed a series of technical problems that urgently need to be solved in practical applications.

[0003] From the perspective of fishing efficiency, existing equipment generally lacks a systematic and coordinated fishing mechanism. Most fishing equipment adopts an independent operation mode for each net, requiring manual deployment, retrieval, and separation of individual nets, making it difficult to achieve large-scale and continuous fishing. For example, traditional fyke nets need to be scattered throughout the aquaculture ponds, requiring manual retrieval of each net for each catch. Especially in large-scale aquaculture scenarios, a single catch consumes a significant amount of time and manpower, resulting in long fishing cycles and low efficiency. The root cause of this inefficient operation mode lies in the fact that the equipment structure design does not form a modular and coordinated combination of fishing units, making it impossible to achieve multi-unit collaborative operation through mechanical or hydraulic systems, and thus failing to meet the high-efficiency production requirements of modern large-scale aquaculture.

[0004] In terms of operational convenience, the lifting and lowering control and net opening and closing of traditional devices rely on manual operation, which is labor-intensive and cumbersome. Taking a common manually operated lifting fishing net as an example, the opening and closing of the net bottom requires manual pulling of ropes. When the water is deep or the aquaculture pond is large, operators need to frequently travel between the pond edge and the net position, and the operational difficulty increases significantly with the complexity of the working environment. In addition, the unreasonable design of the counterweight and lifting structure of some devices leads to problems such as jamming and tilting during the lifting and lowering of the net, further increasing the operational difficulty. The essence of these problems lies in the lack of an automated or semi-automated power drive system, which cannot transform manual operation into mechanized operation driven by water or gravity through mechanical principles, making the fishing process extremely dependent on human skills and physical strength.

[0005] In the protective fishing of crayfish, the existing net structure design fails to adequately address the needs of sorting and protecting the crayfish. On one hand, traditional enclosure nets often use single-mesh netting, making it impossible to grade crayfish of different sizes. This results in juvenile and adult crayfish being caught together, affecting the sustainable growth of the crayfish population in the ponds and increasing the workload of subsequent sorting processes. On the other hand, the edges or lifting components of rigid nets can easily scratch or crush the crayfish during operation. Especially when the net bottom is rapidly raised or lowered, crayfish gather at the bottom due to stress, making them highly susceptible to appendage breakage or shell damage from mechanical impact, affecting the quality and price of marketable crayfish. These problems stem from the limitations of net materials and structural design—rigid materials, while ensuring net strength, lack flexible cushioning; a single enclosure net structure is insufficient for graded fishing, and manual sorting further exacerbates labor costs and the risk of crayfish injury.

[0006] During the technological improvement process, researchers attempted to enhance fishing efficiency by increasing the number of net layers or introducing simple mechanical structures, but faced numerous practical difficulties. For example, the coordinated control of multi-layered nets requires a precise power transmission system, while traditional mechanical transmission methods are prone to failure due to sediment accumulation in underwater environments. Although hydraulic drive solutions can avoid mechanical wear issues, achieving pressure balance and orderly coordination of multi-unit hydraulic systems remains a technical challenge. Furthermore, reducing manufacturing costs and maintenance difficulty while ensuring the structural strength of the device is also a key factor restricting the widespread adoption of high-efficiency fishing equipment—complex mechanical structures often come with high production and maintenance costs, making them difficult to promote and apply in small- and medium-scale aquaculture scenarios.

[0007] In summary, existing crayfish farming and harvesting equipment suffers from significant technical bottlenecks in terms of efficiency, ease of operation, and conservation-oriented harvesting. The core issues lie in the lack of modular, interconnected harvesting units, automated lifting and lowering systems, and tiered screening structures. How to achieve multi-unit collaborative operation, automated lifting of water-driven nets, and efficient separation of crayfish by size through structural innovation is a pressing technical challenge that needs to be overcome in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a crayfish farming and harvesting device with a reasonable structure, high harvesting efficiency, and convenient operation. Through a multi-unit modular design and a hydraulic linkage system, it achieves large-scale continuous harvesting of crayfish, reducing the time and physical exertion of manual net-by-net operation and improving harvesting efficiency. The difference in material and aperture between the inner and outer layers of the enclosure (hard outer layer, soft inner layer, smaller aperture in the inner layer) allows for the grading and screening of crayfish by size. Juvenile crayfish can be returned to the pond through the outer enclosure, while adult crayfish remain in the inner enclosure, reducing subsequent sorting costs. The soft inner enclosure reduces scratches on the crayfish during lifting and lowering, minimizes mechanical collision damage, and improves the quality of marketable crayfish. The hydraulic drive system utilizes gravity and water flow to transmit power, eliminating the need for electricity or complex mechanical structures, reducing equipment costs and maintenance difficulty, and making it suitable for small to medium-sized farming ponds.

[0009] To achieve these objectives and other advantages of this utility model, a crayfish farming and harvesting device is provided, comprising:

[0010] Multiple fishing units are arranged sequentially, and each fishing unit includes:

[0011] A pair of piles, driven vertically into the hard layer at the bottom of the aquaculture pond;

[0012] The outer perimeter netting is square and made of rigid material. The top of the outer perimeter netting is above the water surface, and the bottom is in contact with the rigid layer of the pool bottom. The bottom of the opposite sides is fixed to a pair of pile foundations. The mesh size of the outer perimeter netting is 15-20mm.

[0013] The inner perimeter netting is square and made of soft material, with its top below the water surface and its bottom hanging freely; the mesh size of the inner perimeter netting is smaller than that of the outer perimeter netting; the mesh size of the inner perimeter netting is 8-12mm.

[0014] The support frame is inverted U-shaped, with the bottoms of its two vertical sections fixed to a pair of pile foundations. Both the outer and inner layers of the perimeter fence are located between the two vertical sections of the support frame.

[0015] A fixed pulley is mounted on the top of the bracket;

[0016] The lifting base plate connects to the bottom of the inner perimeter netting and seals its opening, and contacts the hard layer of the pool bottom.

[0017] Multiple guiding mechanisms, each corresponding to a fishing unit, wherein each guiding mechanism includes:

[0018] The upper pole is vertically set, with its top fixed to the top of the support and its bottom extending above the water surface;

[0019] The lower rod is vertically set, and its upper part is slidably connected to the upper rod, while its bottom is fixed to the center of the lifting base plate.

[0020] A hydraulic system, corresponding one-to-one with a fishing unit, includes:

[0021] A counterweight bucket, which is located on or suspended on a bracket;

[0022] The main lifting rope has one end connected to the top of the lower pole and the other end connected to the counterweight bucket after passing over a fixed pulley. When the counterweight bucket pulls down the other end of the main lifting rope, one end of the main lifting rope pulls up the lifting base plate.

[0023] Multiple drain pipes are installed, with one drain pipe corresponding to each of the two counterweight water tanks installed in sequence, and the drain valve of the first counterweight water tank is connected to the inlet of the second counterweight water tank through the drain pipe.

[0024] Preferably, in the crayfish farming and harvesting device, the height of the outer enclosure net is 1.2-1.5m, and the top of the outer enclosure net is 0.2-0.3m above the water surface.

[0025] Preferably, in the crayfish farming and harvesting device, the inner mesh has a hole diameter of 8-12mm and a height of 0.8-1.0m, and the top is kept 0.1-0.2m below the water surface by a buoyancy ring.

[0026] Preferably, in the crayfish farming and harvesting device, the drain pipe of the last counterweight bucket extends to the farming pond.

[0027] Preferably, in the crayfish farming and harvesting device, any harvesting unit further includes:

[0028] The first support plate is L-shaped, and the top of the vertical part of the first support plate is fixed to the top of the bracket. The first support plate is close to the fixed pulley, and the counterweight bucket is selectively located on or suspended on the horizontal part of the first support plate.

[0029] Preferably, in the crayfish farming and harvesting device, a first baffle is provided at the top of the end of the horizontal part of the first support plate away from its vertical part in the vertical direction, and a counterweight bucket is suspended between the first baffle and the vertical part of the first support plate by a rope.

[0030] Preferably, in the crayfish farming and harvesting device, any harvesting unit further includes:

[0031] The second support plate is L-shaped. The top of the vertical part of the second support plate is fixed to the bottom of the horizontal part of the first support plate. The counterweight bucket is selectively suspended on the horizontal part of the second support plate by a rope. In the two counterweight buckets arranged in sequence, when the first counterweight bucket is suspended on the horizontal part of the first support plate corresponding to it by a rope, and the second counterweight bucket is suspended on the horizontal part of the second support plate corresponding to it by a rope, the height of the first counterweight bucket is higher than the height of the second counterweight bucket.

[0032] Preferably, in the crayfish farming and harvesting device, a second baffle is provided vertically at the top of the end of the horizontal part of the second support plate away from its vertical part, and a counterweight bucket is suspended between the second baffle and the vertical part of the second support plate by a rope.

[0033] Preferably, in the crayfish farming and harvesting device, the top of the inner enclosure net is connected to the top of the outer enclosure net by a rope.

[0034] This utility model has at least the following beneficial effects:

[0035] This invention achieves large-scale continuous harvesting of crayfish through a multi-unit modular design and a hydraulic linkage system, reducing the time and physical exertion of manual net-by-net operation and improving harvesting efficiency. The difference in material and mesh size between the inner and outer nets (hard outer layer, soft inner layer, smaller mesh size in the inner layer) allows for the grading and screening of crayfish by size. Juvenile crayfish can be returned to the pond through the outer net, while adult crayfish remain in the inner net, reducing subsequent sorting costs. The soft inner net reduces scratches on the crayfish during lifting and lowering, minimizing mechanical damage and improving the quality of marketable crayfish. The hydraulic drive system utilizes gravity and water flow to transmit power, eliminating the need for electricity or complex mechanical structures, reducing equipment costs and maintenance difficulty, and making it suitable for small to medium-sized aquaculture ponds.

[0036] This invention utilizes the rigid structure and installation dimensions of the outer mesh (top above the water surface, bottom in contact with the hard layer of the pond bottom) to form a closed outer barrier, preventing crayfish from escaping by jumping or burrowing, thus improving harvesting reliability. The standardized dimensions facilitate large-scale production and installation, adapting to ponds of varying depths and silt conditions. The inner mesh, with its buoyancy ring keeping the top below the water surface and coordinated with the lifting bottom plate, ensures that crayfish cannot escape during harvesting, while also facilitating concentrated bait placement and improving trapping efficiency.

[0037] The design of this utility model, featuring a counterweight bucket and support plate, provides a stable power source for the hydraulic system. A staggered suspension structure enables multi-unit coordinated harvesting, utilizing gravity differences to ensure natural water flow transmission. No additional power is required, making operation convenient and the system highly stable. The addition of a limiting baffle further enhances the reliability of the counterweight bucket suspension, reducing the impact of swaying on harvesting operations and making the multi-unit coordinated process more orderly.

[0038] This invention features an inner and outer layer of netting connected at the top by ropes, enhancing the structural stability of the inner layer and ensuring its verticality amidst water flow and shrimp activity, thus guaranteeing the effectiveness of the grading and screening function. The simple and reliable connection method reduces maintenance costs, adapts to the long-term needs of aquaculture environments, and further improves the practicality and overall synergy of the device.

[0039] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a crayfish farming and harvesting device according to an embodiment of the present invention. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0042] It should be noted that in the description of this utility model, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0043] like Figure 1 As shown, this utility model provides a crayfish farming and harvesting device, comprising:

[0044] Multiple fishing units are arranged sequentially, and each fishing unit includes:

[0045] A pair of piles 1, which are driven vertically into the hard layer at the bottom of the aquaculture pond;

[0046] The outer perimeter netting 2 is square and made of rigid material. The top of the outer perimeter netting 2 is higher than the water surface, and the bottom contacts the rigid layer of the pool bottom. The bottom of the opposite sides is fixed to a pair of pile foundations 1. The aperture of the outer perimeter netting 2 is 15-20mm.

[0047] The inner layer of netting 3 is square and made of soft material. Its top is below the water surface and its bottom hangs freely. The aperture of the inner layer of netting 3 is smaller than that of the outer layer of netting 2. The aperture of the inner layer of netting 3 is 8-12mm.

[0048] The support 4 is inverted U-shaped. The bottom of the two vertical parts of the support 4 is fixed to a pair of pile foundations 1 respectively. The outer layer of netting 2 and the inner layer of netting 3 are both located between the two vertical parts of the support 4.

[0049] Fixed pulley 5 is mounted on top of bracket 4;

[0050] The lifting base plate 6 is connected to the bottom of the inner perimeter netting 3 and closes the opening at its bottom, and contacts the hard layer of the pool bottom.

[0051] Multiple guiding mechanisms, each corresponding to a fishing unit, wherein each guiding mechanism includes:

[0052] The upper rod 7 is vertically set, with its top fixed to the top of the bracket 4 and its bottom extending above the water surface;

[0053] The lower rod 8 is vertically set, and its upper part is slidably connected to the upper rod 7, while its bottom is fixed to the center of the lifting base plate 6.

[0054] A hydraulic system, corresponding one-to-one with a fishing unit, includes:

[0055] The counterweight bucket 9 is located on or suspended on the bracket 4;

[0056] The lifting main rope 10 has one end connected to the top of the lower rod 8 and the other end connected to the counterweight water tank 9 after passing over the fixed pulley 5. When the counterweight water tank 9 pulls down the other end of the lifting main rope 10, one end of the lifting main rope 10 pulls up the lifting base plate 6.

[0057] Multiple drain pipes are installed, with one drain pipe corresponding to each of the two counterweight water tanks 9 installed in sequence, and the drain valve of the first counterweight water tank 9 is connected to the inlet of the second counterweight water tank 9 through the drain pipe.

[0058] The pile foundation 1 can be made of metal or concrete poles 2-3 meters long. After being driven into the hard layer of the pool bottom, its exposed height must be suitable for the installation of the support frame 4. The outer perimeter netting 2 uses rigid polyethylene netting or a metal frame netting, fixed to the pile foundation 1 on both sides with bolts or ropes. Its top extends 0.2-0.3 meters above the water surface, and its bottom contacts the hard layer of the pool bottom. The inner perimeter netting 3 uses nylon or polyester soft netting. Its top is kept 0.1-0.2 meters below the water surface by plastic floats, and its bottom hangs naturally. Its top edge is connected to the top of the outer perimeter netting 2 by ropes. The inverted U-shaped support frame 4 is welded from galvanized steel pipes. The bottom of its vertical section is fixed to the outside of the pile foundation 1. The fixed pulley 5 is made of metal and bolted to the top crossbar of the support frame 4. The lifting base plate 6 is made of stainless steel or rigid plastic, with its edges sewn to the bottom of the inner perimeter netting 3 with nylon ropes to ensure tight contact with the hard layer of the pool bottom when closed.

[0059] The upper rod 7 of the guide mechanism is a stainless steel round tube with a diameter of 50mm. Its height is adjusted according to the height of the bracket 4. The top is welded or bolted to the crossbar of the bracket 4, and the bottom is 0.5 meters above the water surface. The lower rod 8 is a round tube of the same material. Its upper part is inserted into the upper rod 7 and slides up and down through a sliding bearing or sleeve. Its bottom is welded to the center of the lifting base plate 6 through a flange to ensure vertical stability during the lifting process.

[0060] The counterweight bucket 9 is a 50-100L plastic cylindrical bucket, suspended from one side of the bracket 4 by a hook. The lifting main rope 10 is made of 8-12mm diameter nylon rope, with one end knotted and fixed to the top of the lower rod 8, and the other end passing over the fixed pulley 5 and connected to the handle of the bucket 9. The drain pipe is a 30-50mm diameter plastic flexible hose. A ball valve is installed at the bottom of the previous bucket 9 as a drain valve, and it is connected to the top inlet of the next bucket 9 through a pipe. The drain pipe of the last bucket 9 extends to the edge of the breeding pond to facilitate drainage backflow.

[0061] Work process:

[0062] During installation, multiple harvesting units are arranged sequentially along the long side of the aquaculture pond, with a spacing of 1-2 meters between adjacent harvesting units. Pile foundation 1 is driven vertically into the hard layer at the bottom of the pond (depth ≥ 1.5 meters). After the support frame 4 is fixed, the inner and outer fencing 2, fixed pulleys 5, and lifting base plate 6 are installed sequentially. The upper rod 7 of the guide mechanism is fixed to the top of the support frame 4, and the lower rod 8 is connected to the center of the lifting base plate 6. Initially, the lifting base plate 6 is located at the bottom of the pond, and the opening at the top of the inner fencing 3 is open. Crayfish can enter the outer area (the area between the outer fencing 2 and the inner fencing 3) through the large aperture of the outer fencing 2, and then swim into the inner layer to feed through the small aperture of the inner fencing 3.

[0063] During harvesting, the counterweight bucket 9 suspended on the support 4 is removed, leaving it suspended in the air. Water is then poured into the first bucket 9 until it is full. Under gravity, the bucket 9 is lifted by the main rope 10 via the fixed pulley 5, causing the lower rod 8 to rise, which in turn raises the lifting plate 6. Adult shrimp are then manually collected from the inner enclosure net 3. After the harvesting of the previous unit is completed, the drain valve of the bucket 9 in the previous unit is opened, and water flows through the drain pipe into the bucket 9 in the next unit, triggering the lifting plate 6 of the next unit to rise synchronously, achieving multi-unit coordinated harvesting. Simultaneously, after the bucket 9 in the previous unit is emptied, the lifting plate 6 falls back under gravity, and the opening at the top of the inner enclosure net 3 reopens, entering the next harvesting cycle.

[0064] Technical Benefits: The multi-unit modular design and hydraulic linkage system significantly improve harvesting efficiency and reduce the time and physical exertion of manual net-by-net operation. The difference in material and mesh size between the inner net 3 and the outer net 2 (outer net 2 is rigid, inner net 3 is soft, and the mesh size of the inner net 3 is smaller than that of the outer net 2) allows for the grading and screening of shrimp by size. Juvenile shrimp can be returned to the pond through the outer net 2, while adult shrimp remain in the inner net 3, reducing subsequent sorting costs. The soft inner net 3 reduces mechanical damage to the shrimp during lifting and lowering, improving the quality of marketable shrimp. The hydraulic drive system utilizes gravity and water flow to transmit power, requiring no electricity, and its simple structure and easy maintenance make it suitable for ponds of different sizes.

[0065] How to use:

[0066] The number of units is determined based on the area of ​​the aquaculture pond (e.g., 5-8 units per acre), and they are arranged in a straight line along the edge of the pond, with a spacing of 1-2 meters between adjacent units.

[0067] Drive pile 1 vertically into the hard layer at the bottom of the pool to ensure that the support 4 is stable and does not shake after installation.

[0068] The outer perimeter netting 2 is fixed to the middle of the pile foundation 1 on both sides, and the top is tied to the crossbar of the support 4. The top of the inner perimeter netting 3 is positioned by a floating ring, and the bottom is sewn to the lifting base plate 6.

[0069] Adjust the length of the lower rod 8 of the guide mechanism so that the lifting base plate 6 hangs naturally 5-10 cm from the bottom of the pool, ensuring close contact with the bottom of the pool when closed.

[0070] The two ends of the lifting main rope 10 are fixed to the top of the lower pole 8 and the counterweight water tank 9, respectively. After passing over the fixed pulley 5, the rope tension is adjusted to ensure that when the water tank 9 is full of water, the lifting base plate 6 can be lifted to 0.2 meters below the water surface.

[0071] The counterweight water tanks 9 of the sequential unit are connected by a drain pipe. The drain valve of the previous water tank 9 is aligned with the water inlet of the next water tank 9. The drain pipe of the last water tank 9 extends to the edge of the pool or directly returns to the pool.

[0072] Fishing operations:

[0073] 1) Trapping stage:

[0074] Feed is evenly distributed into the area directly below the inner layer of the enclosure net in the aquaculture pond, using the crayfish's feeding instincts to lure them towards the harvesting unit. At this point, the outer enclosure net plays a crucial role: its 15-20mm mesh size is installed perpendicular to the pond bottom, with the mesh axis horizontal. Adult crayfish (body width ≤ 20mm), attracted by the feed, can naturally swim horizontally through the mesh of the outer enclosure net to enter the outer area between the outer and inner enclosure nets.

[0075] Adult shrimp can only enter the outer perimeter area by horizontally traversing the mesh of the outer enclosure net through behavioral inducement (feeding tendency), but due to limitations in their biological movement habits (weak vertical climbing ability) and the physical enclosure, they cannot escape in the opposite direction. Specifically, once adult shrimp enter the outer perimeter area, they are immediately blocked by the three-dimensional physical enclosure structure:

[0076] Top sealing: The top of the outer enclosure is 0.3m above the water surface, exceeding the maximum jumping height of crayfish (experiments have shown it to be <0.2m), completely blocking the jumping escape path;

[0077] Bottom sealing: The bottom of the outer perimeter netting contacts the hard layer of the pool bottom, preventing the possibility of escaping back to the main pool from the bottom;

[0078] Lateral blocking: The outer perimeter netting is vertically fixed on both sides by pile foundations, and adjacent units are tightly spliced ​​to form a continuous barrier, eliminating lateral escape gaps.

[0079] In this enclosed environment, when adult shrimp attempt to climb vertically through the outer mesh of the enclosure, they must perform a highly difficult maneuver involving both vertical climbing and precise alignment with the mesh. This results in a success rate of less than 5% for adult shrimp vertically climbing the rigid mesh, and the water resistance further reduces the probability of escape, keeping them confined to the outer area.

[0080] Simultaneously, a juvenile shrimp selection mechanism operates: juvenile shrimp with a body width <15mm can freely pass through the outer perimeter netting in both directions, and if disturbed during harvesting, they quickly return to the main culture pond, achieving sustainable harvesting. Adult shrimp remaining in the outer area, attracted by continuous feed, enter the inner perimeter netting area through the open top of the inner perimeter netting (located 0.2m below the water surface, without netting coverage). The 8-12mm mesh size of the inner perimeter netting allows juvenile shrimp to escape back to the outer area, while adult shrimp (body width >12mm) are intercepted in the inner perimeter netting, completing secondary selection.

[0081] 2) Start fishing:

[0082] The first fishing unit's counterweight bucket 9 is manually filled with clean water (50-100L capacity). Due to gravity, the counterweight bucket 9 pulls the lifting main rope 10 downwards. The lifting main rope 10, after its force is redirected by the fixed pulley 5 at the top of the support 4, pulls upwards at the end connected to the lower rod 8, causing the lower rod 8 to slide upwards along the upper rod 7, thereby pulling the lifting base plate 6 vertically upwards. As the lifting base plate 6 rises, the bottom edge of the inner layer netting 3 moves upwards synchronously, creating a gap between the bottom of the inner layer netting 3 and the pond bottom. Adult shrimp that have already swum into the inner layer netting 3 are trapped inside. The top of the inner layer netting is below the water surface, preventing jumping (the top of the inner layer netting 3 is 0.1-0.2m below the water surface, preventing adult shrimp from jumping out). The 8-12mm mesh size blocks adult shrimp from passing through, and the raised lifting base plate eliminates the possibility of escaping by drilling to the bottom.

[0083] 3) Joint fishing:

[0084] After the first counterweight bucket 9 is filled with water, its bottom drain valve is immediately opened, and the water in the bucket flows into the empty bucket 9 of the next fishing unit through the drain pipe. As the water volume in the next bucket 9 increases, its weight gradually increases and pulls the lifting main rope 10 of the corresponding unit, triggering the lifting base plate 6 of the next unit to rise synchronously. A gap is formed between the bottom of the inner enclosure net 3 and the bottom of the pool. This sequence is used to operate multiple fishing units in turn until the lifting base plate 6 of all units is raised to the highest position and the gap between the bottom of the inner enclosure net 3 and the bottom of the pool reaches its maximum value, thus completing the interception of adult shrimp in the inner enclosure net 3 of each unit.

[0085] 4) Collecting and repositioning the shrimp:

[0086] After all the lifting base plates 6 of the fishing units are fully raised, the operators use nets to collect the adult shrimp from the inner enclosure net 3 from one side of the support 4. After the shrimp collection is completed, the drain valves of all the counterweight water tanks 9 are opened to drain the water from the tanks into the aquaculture pond. With the weight of the counterweight water tanks 9 reduced, the lifting base plates 6, under their own weight and the pulling force of the inner enclosure net 3, can be further pulled down by manpower using the lower rod 8, accelerating the lifting base plates 6 to fall back to the hard layer at the bottom of the pond. The bottom edge of the inner enclosure net 3 is then tightly pressed against the bottom of the pond again by the lifting base plates 6, eliminating the gap between the bottom of the inner enclosure net 3 and the bottom of the pond, restoring it to its initial state before harvesting. At this time, the adult shrimp between the outer enclosure net 2 and the inner enclosure net 3 that have not entered the inner layer continue to be intercepted in the outer area, and can be attracted back into the inner enclosure net 3 in the next trapping stage.

[0087] In another embodiment, the crayfish farming and harvesting device has an outer mesh size of 15-20mm and a height of 1.2-1.5m, with the top of the outer mesh 2 extending 0.2-0.3m above the water surface.

[0088] The outer enclosure net 2 can have a mesh size of 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, etc. This mesh size range allows juvenile shrimp (smaller than the mesh size) to freely pass through the mesh and return to the pond, while intercepting adult shrimp (larger than the mesh size). The outer enclosure net 2 can be made of readily available equipment such as rigid polyethylene netting or metal frame netting, and the material can be existing materials such as polyethylene, polypropylene, or stainless steel. The bottom sides of the outer enclosure net 2 are fixed to a pair of piles 1 with bolts or ropes. During assembly, it is necessary to ensure that the net is perpendicular to the pond bottom to avoid tilting and deformation of the mesh size. During operation, crayfish swim to the outer enclosure net 2. Juvenile shrimp continue to swim into the pond through the mesh of the outer enclosure net 2, while adult shrimp are blocked in the area between the outer enclosure net 2 and the inner enclosure net 3, achieving initial screening of shrimp size.

[0089] The height of the outer enclosure net 2 can be selected from values ​​such as 1.2m, 1.3m, 1.4m, and 1.5m, and the distance of the top above the water surface can be selected from 0.2m, 0.25m, and 0.3m, with the bottom contacting the hard layer of the pond bottom. During installation, first, a pair of piles 1 are driven vertically into the hard layer of the pond bottom. Then, the bottom sides of the outer enclosure net 2 are fixed to the middle of the piles 1, and the top is tied to the bottom of the inverted U-shaped bracket 4 with ropes, ensuring that the bottom of the outer enclosure net contacts the hard layer of the pond bottom. The height of the outer enclosure net 2 must ensure that the top is 0.2-0.3m above the water surface to prevent crayfish from jumping out and escaping. During the breeding process, the outer enclosure net 2 forms a vertical barrier, preventing crayfish from escaping through the top or bottom, further improving the escape prevention effect.

[0090] When installing the outer perimeter netting 2, adjust its height according to the water depth of the aquaculture pond. The depth of the pile foundation 1 in the soil must be greater than 1.5m to ensure stability. The aperture of the outer perimeter netting 2 should be selected based on the average size of the crayfish during the aquaculture cycle. If the target adult crayfish size is 25mm or larger, the aperture of the outer perimeter netting 2 can be set to 18mm to ensure that juvenile crayfish (smaller than 18mm) can pass through while adult crayfish are intercepted.

[0091] For functional testing, crayfish models of different sizes (such as plastic simulated shrimp) can be placed in the breeding pond to observe their passage through the outer mesh 2, and the aperture can be adjusted to meet the grading requirements. In terms of structural design, the rigid material of the outer mesh 2 must be able to withstand the impact of water and the climbing of crayfish. A polyethylene mesh with a thickness of 2-3mm or a stainless steel wire mesh with a diameter of 5mm can be selected.

[0092] Technical Effects: By limiting the aperture and installation dimensions of the outer perimeter netting 2, the system achieves graded screening and escape prevention for crayfish. The 15-20mm aperture effectively separates juvenile and adult crayfish, reducing accidental capture of juveniles and ensuring the sustainable growth of the crayfish population in the pond. The design, with the top protruding above the water surface and the bottom contacting the hard layer of the pond bottom, combined with the structural strength of the rigid material, forms a closed outer barrier, preventing crayfish from escaping by jumping or burrowing, thus improving harvesting reliability. Furthermore, the standardized dimensions (e.g., height 1.2-1.5m) facilitate large-scale production and installation, reduce equipment debugging costs, and are suitable for use in ponds with varying water depths and silt conditions.

[0093] In another embodiment, the crayfish farming and harvesting device has an inner mesh 3 with a mesh size of 8-12mm and a height of 0.8-1.0m, and the top is kept 0.1-0.2m below the water surface by a buoyancy ring.

[0094] The inner mesh can be configured with apertures of 8mm, 9mm, 10mm, 11mm, or 12mm. This aperture is smaller than the outer mesh, effectively preventing adult shrimp from entering the inner area after being screened by the outer mesh, while allowing water exchange and the diffusion of feed odors. The inner mesh can be made of readily available soft materials such as nylon or polyester, whose flexibility reduces scratching damage to the shrimp during harvesting. During assembly, the bottom of the inner mesh is sewn to the lifting base plate with nylon rope, ensuring the bottom opening is tightly sealed initially, while the top hangs naturally and is positioned by a buoyancy ring. During operation, adult shrimp intercepted by the outer mesh move towards the inner mesh and enter the inner area to feed through the 8-12mm aperture, while smaller juvenile shrimp can continue swimming through the inner mesh, allowing for further grading.

[0095] The height of the inner enclosure net can be selected from values ​​such as 0.8m, 0.9m, and 1.0m, and its height is lower than that of the outer enclosure net, ensuring that the top can be kept below the water surface by buoyancy rings. During installation, the inner enclosure net is vertically suspended inside the inverted U-shaped support, with the top fixed in position by buoyancy rings (such as plastic floats, foam floats, or other readily available equipment), and the bottom hanging freely and connected to the lifting base plate. For example, if the height of the outer enclosure net is 1.5m, the height of the inner enclosure net can be selected to be 1.0m, so that the outer enclosure net forms a stable vertical barrier in the water. During the aquaculture process, the height of the inner enclosure net needs to be coordinated with that of the outer enclosure net to ensure that adult shrimp have enough space to enter, while avoiding the top of the net being exposed above the water surface due to excessive height, which would affect the harvesting effect.

[0096] The buoyancy ring can be made from readily available buoyancy devices such as plastic buoys or foam floats. Its diameter or width can be adjusted according to the size of the enclosure net. For example, a 10cm diameter circular plastic buoy can be selected and evenly fixed to the top edge of the inner enclosure net using ropes, keeping the top of the net 0.1m, 0.15m, or 0.2m below the water surface. During assembly, first fix the buoyancy ring to the top of the net, then simply secure the top of the net to the support crossbar with ropes, ensuring the net remains vertical in the water flow and preventing tilting or overturning. During operation, the buoyancy ring supports the top of the net with its own buoyancy, keeping it stably below the water surface. Crayfish cannot escape the inner enclosure net by jumping, and it also facilitates the concentrated placement of bait into the inner area, improving trapping efficiency.

[0097] When installing the inner enclosure net, the height of the inner enclosure net and the position of the buoyancy ring need to be determined based on the height of the outer enclosure net and the water level of the aquaculture pond. The aperture setting needs to be combined with the average size of adult shrimp during the aquaculture cycle. If the target adult shrimp to be caught is ≥25mm in length, the aperture of the inner enclosure net can be selected as 10mm to ensure that adult shrimp cannot pass through but juvenile shrimp can pass through smoothly, reducing the workload of subsequent sorting.

[0098] For functional testing, different sizes of crayfish can be released into the test pond to observe their passage through the inner mesh. The mesh size can be adjusted so that adult crayfish can swim in actively while minimizing the accidental capture rate of juvenile crayfish. Regarding material selection, soft netting must possess tensile and corrosion resistance. Nylon netting with a wire diameter of 0.25mm can be used, as it can withstand crayfish collisions while maintaining a flexible cushioning effect.

[0099] Technical Effects: By limiting the aperture, height, and top position of the inner mesh, targeted trapping and grading of adult shrimp are effectively achieved. The 8-12mm aperture, combined with the 15-20mm aperture of the outer mesh, forms a double-layer screening mechanism. Juvenile shrimp can return to the rearing pond through both layers, while adult shrimp are trapped in the inner mesh area, improving the targeting of the catch. The soft material and buoyancy ring design of the inner mesh ensure stable descent in the water, while the top submerged below the water surface prevents shrimp escape. The bottom, linked to a lifting plate, allows for quick closure of the opening, increasing harvesting efficiency. Simultaneously, the flexible mesh reduces mechanical damage to the shrimp, helping to maintain their integrity and meeting the requirements of conservation-oriented harvesting. Standardized dimensions (e.g., height 0.8-1.0m) facilitate coordination with the outer mesh and other components, reducing installation and adjustment difficulties, and making it suitable for crayfish farming scenarios of different scales.

[0100] In another embodiment, the drain pipe of the last counterweight water tank 9 in the crayfish farming and harvesting device extends to the farming pond.

[0101] The length of the drain pipe can be determined according to the layout of the aquaculture pond, for example, choosing a pipe of 5-10 meters to ensure that the end of the drain pipe of the last counterweight water tank 9 can extend to the edge of the aquaculture pond or the designated drainage area. The drain pipe can be a readily available piece of equipment such as a common plastic hose or PVC pipe, and the material can be existing materials such as polyethylene and polypropylene, which have the characteristics of corrosion resistance and good flexibility. During assembly, one end of the drain pipe is connected to the drain valve of the last counterweight water tank 9, and the other end extends into the aquaculture pond or the drainage ditch on the pond side. It is necessary to avoid pipe bends and blockages to ensure smooth water flow. During operation, when the last counterweight water tank 9 drains, the water is directly discharged into the aquaculture pond through the drain pipe, realizing the recycling of water resources and preventing water accumulation from causing additional burden on the harvesting device.

[0102] When installing the drainage pipe, the pipe routing needs to be adjusted according to the arrangement of the fishing units and the shape of the aquaculture pond. For example, it can be laid along the bottom of the support 4 or the edge of the pond and secured with clips or ropes to prevent displacement. Regarding parameter settings, the diameter of the drainage pipe can be consistent with the drainage pipe in the hydraulic system described above (e.g., 30-50mm) to ensure the drainage speed matches the capacity of the counterweight tank 9. For example, a 100L counterweight tank 9 should be emptied within 2-3 minutes. For functional testing, water can be added to the last counterweight tank 9 and the drain valve opened to observe whether the water flows smoothly into the aquaculture pond. The pipe slope or length can be adjusted until no water remains. In terms of structural design, a filter screen can be installed at the end of the drainage pipe to prevent debris from entering and clogging the pipe.

[0103] Technical Benefits: By extending the drain pipe of the last counterweight tank 9 to the aquaculture pond, the hydraulic system's drainage is recycled, reducing water waste and maintaining a stable water level in the pond. This design avoids the environmental impact that could result from direct discharge outside the pond, meeting the environmental protection requirements of aquaculture. Furthermore, the rational arrangement of the drain pipes prevents the counterweight tank 9 from impacting the harvesting device during drainage, improving system stability and ease of operation. Especially during multi-unit coordinated harvesting, it ensures that the drainage from the last unit does not affect the overall balance of the system.

[0104] In another embodiment, any one of the harvesting units in the crayfish farming and harvesting apparatus further includes:

[0105] The first support plate 11 is L-shaped. The top of the vertical part of the first support plate 11 is fixed to the top of the bracket 4. The first support plate 11 is close to the fixed pulley 5. The counterweight water bucket 9 is selectively located on or suspended on the horizontal part of the first support plate 11.

[0106] The first support plate 11 can be an L-shaped component made of metal (such as stainless steel or galvanized steel plate). The height of the vertical part can be set according to the height of the bracket 4, for example, 15-20cm, and the length of the horizontal part can be selected as 20-30cm to ensure stable support for the counterweight water tank 9. During installation, the top of the vertical part of the first support plate 11 is fixed to the top crossbar of the inverted U-shaped bracket 4 by bolts or welding, and is located on one side of the fixed pulley 5, so that the counterweight water tank 9 is close to the fixed pulley 5 after being suspended, which facilitates the even distribution of force when the lifting main rope 10 passes over the fixed pulley 5. The corners of the L-shaped structure can be rounded to avoid stress concentration and breakage. The material thickness can be selected as 3-5mm to ensure sufficient structural strength.

[0107] The counterweight bucket 9 can be a cylindrical plastic bucket (e.g., 50-100L capacity) and can be selectively placed or hung on the horizontal part of the first support plate 11 using a handle or hook. For example, when fishing is to be started, the counterweight bucket 9 is hung on the hook on the horizontal part, and its gravity pulls the main rope 10; after fishing, the bucket 9 can be removed and the accumulated water drained. During assembly, the surface of the horizontal part can be provided with anti-slip textures or rubber pads to prevent the bucket 9 from sliding when placed, and when suspended, it is fixed in the holes on the edge of the horizontal part by a rope or metal hook.

[0108] When installing the first support plate 11, ensure that its vertical part is firmly connected to the top of the bracket 4, its horizontal part remains horizontal, and it is positioned close to the fixed pulley 5 (e.g., 10-15cm away from the fixed pulley 5) to shorten the winding distance of the lifting main rope 10 and reduce friction. Regarding parameter settings, the size of the support plate must match the counterweight bucket 9. For example, if the bottom diameter of a 100L bucket 9 is approximately 30cm, the length of the horizontal part can be set to 35cm to ensure the stability of the center of gravity after the bucket 9 is suspended. As for the source of materials, the L-shaped support plate can be customized at a hardware processing shop, or readily available industrial bracket 4 accessories can be used.

[0109] In terms of functional testing, the deformation of the first support plate 11 can be observed by suspending a counterweight bucket 9 fully loaded with water to ensure that its load-bearing capacity meets the requirements (e.g., load ≥ 100 kg). In terms of structural design, the connection point between the first support plate 11 and the bracket 4 should avoid the installation position of the fixed pulley 5 to prevent mutual interference and affect the normal operation of the lifting main rope 10.

[0110] Technical benefits: The first support plate 11 provides a stable installation position for the counterweight bucket 9. Its L-shaped structure and fixation to the top of the bracket 4 ensure stability when suspended or placed, preventing uneven stress on the lifting main rope 10 due to positional shifts, which would affect the normal lifting and lowering of the lifting base plate 6. The design near the fixed pulley 5 shortens the force transmission path, allowing the weight of the counterweight bucket 9 to more efficiently pull the lifting base plate 6 through the lifting main rope 10, improving the smoothness of the harvesting operation. Furthermore, the selective installation method (placement or suspension) increases the flexibility of the device, allowing the position of the bucket 9 to be adjusted according to actual harvesting needs, adapting to different water depths or crayfish densities, while also facilitating manual operation and maintenance.

[0111] In another embodiment, in the crayfish farming and harvesting device, a first baffle is provided vertically at the top of the end of the horizontal part of the first support plate 11 away from its vertical part, and a counterweight bucket 9 is hung between the first baffle and the vertical part of the first support plate 11 by a rope.

[0112] The first baffle can be made of metal or rigid plastic, with a height of 5-10cm, a width consistent with the horizontal width of the first support plate 11 (e.g., 20-30cm), and a thickness of 2-3mm. During installation, the first baffle is fixed to the top end of the horizontal section of the first support plate 11 by bolts or welding, perpendicular to the vertical section, forming an "L-shaped support plate + vertical baffle" limiting structure. For example, if the horizontal length of the first support plate 11 is 30cm, the baffle can be positioned 28cm from the vertical section, leaving a 2cm installation space to ensure that the counterweight bucket 9 is suspended in the area between the baffle and the vertical section.

[0113] The counterweight bucket 9 is suspended between the first baffle and the vertical part of the first support plate 11 by a nylon rope or steel wire rope. One end of the rope is tied to the handle or a pre-set hanging ring on the bucket 9, and the other end is wrapped around the top of the first baffle and fixed in a hook or hole on the vertical part of the support plate. During assembly, the rope length needs to be adjusted so that the center of gravity of the bucket 9 is above the horizontal part of the support plate after suspension to avoid tilting. For example, if the hanging ring of the bucket 9 is 20cm above the bottom of the bucket, the rope is wrapped around the baffle (8cm high) and fixed 15cm above the horizontal part of the vertical part, ensuring that there is a 5cm gap between the bottom of the bucket 9 and the horizontal part of the support plate, so that the bucket 9 can hang freely when draining water.

[0114] When installing the first baffle, ensure it is perpendicular to the horizontal part of the first support plate 11 and accurately positioned to prevent the bucket 9 from swaying after suspension due to baffle misalignment. Regarding parameter settings, the baffle height must be greater than half the height of the bucket 9 handle (e.g., if the handle is 6cm high, the baffle height is 8cm) to ensure the rope is effectively limited after passing over the baffle. As for the material, the baffle can be made of the same material as the first support plate 11 (e.g., stainless steel), and can be integrally formed during hardware processing or added later.

[0115] For functional testing, the stress on the baffle and rope can be observed by suspending a bucket 9 fully loaded with water to ensure there is no loosening or deformation. In terms of structural design, the top of the baffle can be rounded to reduce rope wear and extend its service life.

[0116] Technical Effects: The first baffle provides a clearly defined suspension limit area for the counterweight bucket 9. By cooperating with the vertical part of the first support plate 11, it forms a stable triangular suspension structure, preventing the bucket 9 from sliding towards the horizontal end or detaching from the support plate under gravity. The design of the rope bypassing the baffle increases the friction of the suspension system, keeping the bucket 9 in a fixed position during lifting or lowering, preventing the lifting main rope 10 from becoming entangled or unevenly stressed due to swaying, thus ensuring the smooth operation of the lifting base plate 6. Furthermore, the limiting structure facilitates quick manual suspension or removal of the bucket 9, improving operational convenience, especially during multi-unit coordinated fishing, ensuring the consistent position of each counterweight bucket 9 and guaranteeing the orderly operation of the hydraulic system.

[0117] In another embodiment, any one of the harvesting units in the crayfish farming and harvesting apparatus further includes:

[0118] The second support plate 12 is L-shaped. The top of the vertical part of the second support plate 12 is fixed to the bottom of the horizontal part of the first support plate 11. The counterweight bucket 9 is selectively hung on the horizontal part of the second support plate 12 by a rope. In the two counterweight buckets 9 arranged in sequence, when the first counterweight bucket 9 is hung on the horizontal part of the first support plate 11 corresponding to it by a rope, and the second counterweight bucket 9 is hung on the horizontal part of the second support plate 12 corresponding to it by a rope, the height of the first counterweight bucket 9 is higher than the height of the second counterweight bucket 9.

[0119] The second support plate 12 can be an L-shaped component made of metal (such as stainless steel or galvanized steel plate). The vertical height can be set to 10-15cm, and the horizontal length is similar to that of the first support plate 11 (e.g., 20-30cm), with a thickness of 3-5mm. During installation, the top of the vertical part of the second support plate 12 is fixed to the bottom of the horizontal part of the first support plate 11 by bolts or welding, forming a vertically superimposed "T-shaped" structure to ensure even force distribution. For example, if the horizontal length of the first support plate 11 is 30cm, the horizontal part of the second support plate 12 can extend 25cm below it to facilitate the suspension of the counterweight bucket 9.

[0120] The counterweight bucket 9 is suspended from the horizontal part of the second support plate 12 by a nylon rope or steel wire rope. Hooks or holes (such as 5mm diameter round holes) can be pre-set on the surface of the horizontal part to secure the rope end. For example, the handle of the bucket 9 can be secured by passing the rope through the hole in the horizontal part and tying a knot, or it can be directly hung on a metal hook on the edge of the horizontal part. When suspending, the rope length should be adjusted so that the bottom of the bucket 9 is ≥50cm from the bottom of the pool to avoid touching the bottom and affecting drainage.

[0121] Since the second support plate 12 is fixed to the bottom of the horizontal part of the first support plate 11, the suspension position of the first counterweight water bucket 9 (hanging on the first support plate 11) is higher than that of the second one (hanging on the second support plate 12). The height difference is usually the sum of the height of the vertical part of the first support plate 11 and the height of the vertical part of the second support plate 12 (e.g., the vertical part of the first support plate 11 is 15cm high, the vertical part of the second support plate 12 is 10cm high, and the total height difference is 25cm). During assembly, it is necessary to ensure that the drain pipes of adjacent units flow from the higher water bucket 9 (first support plate 11) to the lower water bucket 9 (second support plate 12), using gravity to achieve natural water flow.

[0122] During installation, first fix the first support plate 11 to the top of the bracket 4, then fix the vertical part of the second support plate 12 to the bottom of the horizontal part of the first support plate 11, forming a two-layer suspension structure. In the sequential units, the counterweight water bucket 9 of the previous unit is hung on the horizontal part of the first support plate 11, and the next unit is hung on the horizontal part of the second support plate 12. The two are connected by a drain pipe (the drain valve of the previous water bucket 9 is lower than the inlet of the next water bucket 9). When water is poured into the first water bucket 9, its gravity pulls the lifting base plate 6 to rise. After the catch is completed, the drain valve is opened, and the water flows automatically into the lower water bucket 9 of the next unit due to the height difference. Then, the lower water bucket 9 of the next unit is removed, allowing it to fall downwards under gravity, triggering the lifting base plate 6 of the next unit to move. In terms of parameter settings, the height difference must be greater than the diameter of the drain pipe (e.g., 30-50mm) to ensure smooth water flow and avoid siphoning.

[0123] Regarding the source of raw materials, the second support plate 12 can be the same as the first support plate 11, either custom-made at a hardware processing shop or by selecting four standard L-shaped brackets. During functional testing, the water flow rate between adjacent water tanks 9 is observed by filling with water, and the height difference is adjusted to control the drainage time at 5-10 minutes per tank, ensuring a stable linkage rhythm.

[0124] Technical Benefits: The second support plate 12 creates a staggered suspension structure for the sequentially weighted buckets 9, utilizing gravity differences to achieve automatic linkage of the hydraulic system. This allows for the orderly transfer of multi-unit harvesting operations without additional power. The height difference design ensures natural water flow, preventing backflow or blockage and improving system stability. Simultaneously, the compact double-layer suspension structure occupies little space, facilitating multi-unit linkage within the limited area of ​​the support 4, making it particularly suitable for high-density harvesting unit layouts. The selective suspension method (buckets 9 can be hung on either the first support plate 11 or the second support plate 12) increases the flexibility of the device, allowing the position of buckets 9 to be adjusted according to the width of the aquaculture pond or the harvesting sequence, adapting to different operational needs and reducing manual adjustment costs.

[0125] In another embodiment, in the crayfish farming and harvesting device, a second baffle is provided vertically at the top of the end of the horizontal part of the second support plate 12 away from its vertical part, and the counterweight bucket 9 is hung between the second baffle and the vertical part of the second support plate 12 by a rope.

[0126] The second baffle can be made of metal or rigid plastic, with a height of 5-10cm, a width matching the horizontal width of the second support plate 12 (e.g., 20-30cm), and a thickness of 2-3mm. During installation, the second baffle is fixed to the top end of the horizontal section of the second support plate 12 by bolts or welding, perpendicular to the vertical section, forming a limiting structure. For example, if the horizontal length of the second support plate 12 is 25cm, the baffle can be positioned 23cm from the vertical section, leaving a 2cm installation space to ensure that the counterweight bucket 9 is suspended in the area between the baffle and the vertical section. The top of the baffle can be rounded to reduce rope wear.

[0127] The counterweight bucket 9 is suspended between the second baffle and the vertical part of the second support plate 12 by a nylon rope or steel wire rope. One end of the rope is tied to the handle or hanging ring on the bucket 9, and the other end is wrapped around the top of the second baffle and fixed in the hook or hole on the vertical part of the support plate. During assembly, the rope length needs to be adjusted so that the center of gravity of the bucket 9 is above the horizontal part of the support plate after suspension, to avoid tilting. For example, if the hanging ring of the bucket 9 is 20cm above the bottom of the bucket, the rope is wrapped around the baffle (8cm high) and fixed at 12cm above the horizontal part of the vertical part, ensuring that the bottom of the bucket 9 has an 8cm suspension distance from the horizontal part of the support plate, so that the bucket 9 can hang freely without touching the bottom when draining water.

[0128] When installing the second baffle, ensure it is perpendicular to the horizontal part of the second support plate 12 and accurately positioned to prevent the bucket 9 from swaying after suspension due to baffle misalignment. Regarding parameter settings, the baffle height must be greater than half the height of the bucket 9 handle (e.g., if the handle is 6cm high, the baffle height is 8cm) to ensure the rope is effectively limited after passing over the baffle. As for the material, the second baffle can be made of the same material as the second support plate 12 (e.g., stainless steel), and can be integrally formed during hardware processing or added later.

[0129] In terms of functional testing, the stress on the baffle and rope can be observed by suspending a fully loaded water bucket 9 to ensure there is no loosening or deformation. Structurally, triangular reinforcing ribs can be added at the connection between the horizontal and vertical parts of the second support plate 12, but additional technical features should be avoided. In actual operation, the two sequentially arranged counterweight water buckets 9 form a height difference through the limiting effect of the first and second baffles. The drain valve of the first water bucket 9 is connected to the inlet of the second water bucket 9 through a drain pipe, utilizing gravity to achieve a natural flow of water from high to low, triggering multi-unit coordinated harvesting.

[0130] Technical Effects: The second baffle provides a stable suspension limit for the counterweight bucket 9. By cooperating with the vertical part of the second support plate 12, it forms a closed suspension space, preventing the bucket 9 from sliding towards the horizontal end or detaching from the support plate under gravity. The design of the rope bypassing the baffle increases the stability of the suspension system, reduces the impact of bucket 9 swaying on the lifting main rope 10, and ensures the smooth lifting of the lifting base plate 6. Furthermore, the limiting structure facilitates quick manual adjustment of the bucket 9's position, especially in multi-unit linkage scenarios. The baffle allows for accurate alignment of the drain pipe interface, preventing water leakage or pipe twisting and improving the reliability of the hydraulic system. The height difference, combined with the baffle's limiting function, makes the sequential drainage process of the buckets 9 more orderly, reducing manual intervention and adapting to the needs of large-scale fishing.

[0131] In another embodiment, in the crayfish farming and harvesting device, the top of the inner enclosure 3 is connected to the top of the outer enclosure 2 by a rope.

[0132] The ropes connecting the top of the inner layer netting 3 and the outer layer netting 2 can be readily available ropes such as nylon rope, polyester rope, or steel wire rope, with a diameter of 3-5mm and sufficient tensile strength. During assembly, one end of the rope is fixed to the top edge of the inner layer netting 3 using nylon cable ties or metal rings, and the other end is correspondingly fixed to the top edge of the outer layer netting 2. A connection point is set every 50-100cm to ensure that the tops of the two layers of netting remain parallel and evenly spaced. For example, if the circumference of the top of the inner layer netting 3 is 4m, a connection point can be set every 80cm, for a total of 5 connections. The length of the rope needs to be adjusted according to the spacing between the inner and outer layers of netting 2 to ensure that the inner layer netting 3 remains vertical when hanging naturally, avoiding deformation of the netting due to excessively tight or loose ropes.

[0133] During operation, the inner and outer layers of netting 2 are connected at the top by ropes. The inner layer of netting 3 remains stable thanks to the rigid structure of the outer layer of netting 2. This reduces the swaying of the inner layer of netting 3, especially under the impact of water flow or crayfish activity, ensuring that its top remains below the water surface. When the lifting base plate 6 is raised or lowered, the bottom of the inner layer of netting 3 moves with the lifting base plate 6, while the top remains fixed due to the rope connection, forming a stable vertical surface for the inner layer of netting 3, making it easier for crayfish to swim into the inner area through the mesh.

[0134] During installation, first fix the outer layer of netting 2 to the bracket 4 and the pile foundation 1. Then, position the top of the inner layer of netting 3 below the water surface using a buoyancy ring. Finally, connect the corresponding positions of the tops of the inner layer of netting 3 and the outer layer of netting 2 with ropes. Regarding parameter settings, the spacing between connection points can be adjusted according to the size of the netting. For example, for a square netting with a side length of 2m, the spacing between connection points can be set to 1m to ensure uniform stress distribution.

[0135] In terms of functional testing, the stability of the inner and outer layers of netting 2 can be observed by simulating water flow impact, and the rope tension can be adjusted until the inner layer of netting 3 does not sway significantly. In terms of structural design, the connection point between the rope and the netting can be a slipknot, which is convenient for disassembly and maintenance, while avoiding the rope from rotting and breaking due to long-term soaking.

[0136] Technical Effects: Connecting the tops of the inner and outer netting layers 2 with ropes enhances the structural stability of the inner netting layer 3, ensuring its verticality during water flow and harvesting operations, and guaranteeing the effectiveness of the aperture screening function. The connection design reduces independent swaying of the inner netting layer 3, and, in conjunction with buoyancy rings, fixes its top position, preventing tilting due to wind, waves, or shrimp activity, which could hinder crayfish from swimming in. Furthermore, the rope connection method is simple, reliable, low-cost, and easy to maintain, suitable for long-term use in aquaculture environments. It also enhances the overall synergy of the device, creating a stable double-layer structure between the inner and outer netting layers 2, thus improving the efficiency of graded harvesting.

[0137] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A crayfish farming and harvesting device, characterized in that, include: Multiple fishing units are arranged sequentially, and each fishing unit includes: A pair of piles, driven vertically into the hard layer at the bottom of the aquaculture pond; The outer perimeter netting is square and made of rigid material. The top of the outer perimeter netting is above the water surface, and the bottom is in contact with the rigid layer of the pool bottom. The bottom of the opposite sides is fixed to a pair of pile foundations. The mesh size of the outer perimeter netting is 15-20mm. The inner perimeter netting is square and made of soft material, with its top below the water surface and its bottom hanging freely; the mesh size of the inner perimeter netting is smaller than that of the outer perimeter netting; the mesh size of the inner perimeter netting is 8-12mm. The support frame is inverted U-shaped, with the bottoms of its two vertical sections fixed to a pair of pile foundations. Both the outer and inner layers of the perimeter fence are located between the two vertical sections of the support frame. A fixed pulley is mounted on the top of the bracket; The lifting base plate connects to the bottom of the inner perimeter netting and closes the opening at its bottom, while also contacting the hard layer at the bottom of the pool. Multiple guiding mechanisms, each corresponding to a fishing unit, wherein each guiding mechanism includes: The upper pole is vertically set, with its top fixed to the top of the support and its bottom extending above the water surface; The lower rod is vertically set, and its upper part is slidably connected to the upper rod, while its bottom is fixed to the center of the lifting base plate. A hydraulic system, corresponding one-to-one with a fishing unit, includes: A counterweight bucket, which is located on or suspended on a bracket; The main lifting rope has one end connected to the top of the lower pole and the other end connected to the counterweight bucket after passing over a fixed pulley. When the counterweight bucket pulls down the other end of the main lifting rope, one end of the main lifting rope pulls up the lifting base plate. Multiple drain pipes are installed, with one drain pipe corresponding to each of the two counterweight water tanks installed in sequence, and the drain valve of the first counterweight water tank is connected to the inlet of the second counterweight water tank through the drain pipe.

2. The crayfish farming and harvesting device as described in claim 1, characterized in that, The outer perimeter netting is 1.2-1.5m high, and the top of the outer perimeter netting is 0.2-0.3m above the water surface.

3. The crayfish farming and harvesting device as described in claim 1, characterized in that, The height of the inner perimeter net is 0.8-1.0m, and the top is kept 0.1-0.2m below the water surface by a buoyancy ring.

4. The crayfish farming and harvesting device as described in claim 1, characterized in that, The drain pipe of the last counterweight bucket extends to the aquaculture pond.

5. The crayfish farming and harvesting device as described in claim 1, characterized in that, Each fishing unit also includes: The first support plate is L-shaped, and the top of the vertical part of the first support plate is fixed to the top of the bracket. The first support plate is close to the fixed pulley, and the counterweight bucket is selectively located on or suspended on the horizontal part of the first support plate.

6. The crayfish farming and harvesting device as described in claim 5, characterized in that, A first baffle is provided vertically at the top of the horizontal part of the first support plate away from its vertical part, and a counterweight bucket is suspended between the first baffle and the vertical part of the first support plate by a rope.

7. The crayfish farming and harvesting device as described in claim 6, characterized in that, Each fishing unit also includes: The second support plate is L-shaped. The top of the vertical part of the second support plate is fixed to the bottom of the horizontal part of the first support plate. The counterweight bucket is selectively suspended on the horizontal part of the second support plate by a rope. In the two counterweight buckets arranged in sequence, when the first counterweight bucket is suspended on the horizontal part of the first support plate corresponding to it by a rope, and the second counterweight bucket is suspended on the horizontal part of the second support plate corresponding to it by a rope, the height of the first counterweight bucket is higher than the height of the second counterweight bucket.

8. The crayfish farming and harvesting device as described in claim 7, characterized in that, A second baffle is provided vertically at the top of the horizontal part of the second support plate away from its vertical part, and a counterweight bucket is suspended between the second baffle and the vertical part of the second support plate by a rope.

9. The crayfish farming and harvesting device as described in claim 1, characterized in that, The top of the inner perimeter fence is connected to the top of the outer perimeter fence by ropes.

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